This invention relates generally to a conveyor transfer system and, more particularly, to a method and mechanism for transferring objects from a primary conveyor to a secondary conveyor that is moving in a direction normal to the direction of the primary conveyor. The prior art includes a wide variety of techniques and mechanisms for transferring an article being transferred along a primary conveyor to a secondary conveyor that is moving in a different direction, usually in a direction that is normal to the transfer direction of the primary conveyor. For example, in U.S. Pat. No. 5,887,699, articles are transferred from a primary conveyor to a secondary conveyor by a rotating mechanism that includes an extending arm that is mounted for rotation and operated by a hydraulic cylinder such that a portion of the article extends across the side of the primary conveyor and is frictionally engaged by the secondary conveyor. Another example of a prior art conveyor diverting system is shown in U.S. Pat. No. 5,927,465 that utilizes a pair of diverting tracks and diverting gates that are moved into position to divert articles that are to be directed to the secondary conveyor. Generally, the prior art devices include structural mechanism such as turning devices, arms for rotating the articles and pivoting mechanism for re-orienting the articles to be transferred to the secondary conveyor. These prior art devices depend upon the article and the structural mechanism engaging in a predetermined way and are susceptible to malfunctioning if the size or shape of the article changes or the article is not orientated on the primary conveyor as anticipated. Also, the diverting arms, turning devices and pivoting mechanisms are, since they are exposed, vulnerable to being bent, broken or twisted, thus rendering them inoperative for their intended purpose. Furthermore, the diverting mechanisms are susceptible to wear and, when worn, they malfunction. The prior art devices are also complex, occupy considerable space, clutter and obstruct the conveyor area and are expensive to produce and maintain. Furthermore, many of the prior art devices are designed for specific articles and cannot be relied upon to function satisfactorily with other articles. As a result, there is a need for a simple, compact, reliable, adaptable and inexpensive mechanism for transferring articles from a primary conveyor to a secondary conveyor that extends at an angle to the primary conveyor.
This principal object of this invention is to provide a method and mechanism for transferring an article being conveyed along a primary conveyor to a secondary conveyor that extends normal to said primary conveyor in a manner that overcomes the above discussed shortcomings of the prior art. To accomplish this, Applicant has provided a primary conveyor for conveying individual objects in a first direction toward its discharge end and a secondary conveyor for receiving objects at a receiving location from said discharge end of the first conveyor. The secondary conveyor then conveys the individual objects in a direction that is at an angle to said first direction. The first and secondary conveyors are arranged with respect to each other such that, when the conveyed objects reach the discharge end of said first conveyor, they are deposited on the receiving location of said second conveyor. The second conveyor has a flat support surface over which a perforated continuous conveyor belt extends. A vacuum plenum, having a flat upper surface, is inlayed in the flat support surface such that its flat upper surface lies in the plane of the flat support surface. There are slotted openings formed in the flat upper surface of the vacuum plenum. A vacuum source is connected to the vacuum plenum for creating a vacuum in said plenum that pulls air through the perforated continuous conveyor belt that moves over the flat support surface. The vacuum causes objects that are deposited on the secondary conveyor at the receiving location to be pulled to and held against the upper surface of the perforated continuous conveyor belt. The vacuum is sufficiently strong to stop the movement of the objects in the direction of the primary conveyor and to hold the objects against the upper surface the of perforated continuous conveyor belt. Once the movement of an object in the direction of the primary conveyor has been stopped, the object is conveyed along the second conveyor without the need for a vacuum to hold it against the upper surface of the perforated continuous conveyor. In accordance with Applicant""s invention, there are no external arms, trays or diverters that can be bent or broken and, thus, disable the transfer mechanism. Applicant""s mechanism provides for a positive transfer from the primary to the secondary conveyor that can be adjusted for objects of various sizes and weights by merely changing the level of the vacuum.